The invention relates to a sensor according to the preamble of claim 1 as well as to a method of its production.
Sensors of this type are e.g. flow or temperature sensors, where at least a part of the measuring element is arranged on a membrane. This membrane has often a thickness of a few micrometers only and spans an opening or recess in the semiconductor device.
Preferably, further active electronic components are integrated on the semiconductor device of sensors of this type, such as transistors for amplifiers or reference voltage sources.
The membrane is usually formed by the layers deposited during the production of the circuit, wherein the semiconductor below the layers is etched away. The layers that are deposited in most of the conventional production processes, are, however, usually under compressive stress, i.e. pressure forces are acting within the plane of the layer, e.g. because the layers were applied at elevated temperatures and contracted less than the substrate while cooling down. The magnitude of the compressive stress depends on the manufacturing process and on the layer structure of the membrane. This compressive stress can lead to an undesired buckling of the membrane, which renders it mechanically unstable.